Aircraft engine: Hirth HM-504A
|Configuration||4-cylinder inverted inline|
|Displacement||4 l (244 cu in)|
|Weight||104 kg (229 lb)|
|Maximum power||105 hp at 2,530 RPM|
|Climb power||85 hp at 2,360 RPM|
The engine was designed at the Hirth Motoren company in Stuttgart. During 1934–35 Hirth developed a concept of manufacturing different types of engines, varying in respect of the power output and capacity, yet composed of unified elements such as cylinders, crankshaft and timing gear. This conception was very beneficial from the technical and economical point of view. A family of the “500” series engines was developed – versions 504, 506 and 508. In the 504A version the crankcase was cast in electron, leading to reduction in the weight of the engine. It was used in the Bücker Bü 131 Jungmann, Bücker Bü 181 Bestmann and Arado Ar 79 aircraft. Production totalled about 6,000 examples.